Inwardly rectifying potassium channels in Drosophila

Inwardly rectifying potassium channels (Kir) are a special subset of potassium selective ion channels which pass potassium more easily into rather than out of the cell. These channels mediate a variety of cellular functions, including control of membrane resting potential, maintenance of potassium homeostasis and regulation of cellular metabolism. Given the existence of fifteen Kir genes in mammals, current genetic studies using mutant animals that lack a single channel may have missed many important physiological functions of these channels due to gene redundancy. This issue can be circumvented by using a simple model organism like Drosophila, whose genome encodes only 3 Kir proteins. The sophisticated genetic approaches of Drosophila may also provide powerful tools to identify additional regulation mechanisms of Kir channels. Here we provide an overview of the progress made in elucidating the function of Drosophila Kir channels. The knowledge of Drosophila Kir channels may lead us to uncover novel functions and regulation mechanisms of human Kir channels and help on pathological studies of related diseases

The putative Na(+)/Cl(-)-dependent neurotransmitter/osmolyte transporter inebriated in the Drosophila hindgut is essential for the maintenance of systemic water homeostasis

Most organisms are able to maintain systemic water homeostasis over a wide range of external or dietary osmolarities. The excretory system, composed of the kidneys in mammals and the Malpighian tubules and hindgut in insects, can increase water conservation and absorption to maintain systemic water homeostasis, which enables organisms to tolerate external hypertonicity or desiccation. However, the mechanisms underlying the maintenance of systemic water homeostasis by the excretory system have not been fully characterized. In the present study, we found that the putative Na(+)/Cl(-)-dependent neurotransmitter/osmolyte transporter inebriated (ine) is expressed in the basolateral membrane of anterior hindgut epithelial cells. This was confirmed by comparison with a known basolateral localized protein, the alpha subunit of Na(+)-K(+) ATPase (ATPalpha). Under external hypertonicity, loss of ine in the hindgut epithelium results in severe dehydration without damage to the hindgut epithelial cells, implicating a physiological failure of water conservation/absorption. We also found that hindgut expression of ine is required for water conservation under desiccating conditions. Importantly, specific expression of ine in the hindgut epithelium can completely restore disrupted systemic water homeostasis in ine mutants under both conditions. Therefore, ine in the Drosophila hindgut is essential for the maintenance of systemic water homeostasis

Calcineurin B-Like Proteins CBL4 and CBL10 Mediate Two Independent Salt Tolerance Pathways in Arabidopsis.

In Arabidopsis, the salt overly sensitive (SOS) pathway, consisting of calcineurin B-like protein 4 (CBL4/SOS3), CBL-interacting protein kinase 24 (CIPK24/SOS2) and SOS1, has been well defined as a crucial mechanism to control cellular ion homoeostasis by extruding Na+ to the extracellular space, thus conferring salt tolerance in plants. CBL10 also plays a critical role in salt tolerance possibly by the activation of Na+ compartmentation into the vacuole. However, the functional relationship of the SOS and CBL10-regulated processes remains unclear. Here, we analyzed the genetic interaction between CBL4 and CBL10 and found that the cbl4 cbl10 double mutant was dramatically more sensitive to salt as compared to the cbl4 and cbl10 single mutants, suggesting that CBL4 and CBL10 each directs a different salt-tolerance pathway. Furthermore, the cbl4 cbl10 and cipk24 cbl10 double mutants were more sensitive than the cipk24 single mutant, suggesting that CBL10 directs a process involving CIPK24 and other partners different from the SOS pathway. Although the cbl4 cbl10, cipk24 cbl10, and sos1 cbl10 double mutants showed comparable salt-sensitive phenotype to sos1 at the whole plant level, they all accumulated much lower Na+ as compared to sos1 under high salt conditions, suggesting that CBL10 regulates additional unknown transport processes that play distinct roles from the SOS1 in Na+ homeostasis

Extreme case of Faraday effect: magnetic splitting of ultrashort laser pulses in plasmas

The Faraday effect, caused by a magnetic-field-induced change in the optical properties, takes place in a vast variety of systems from a single atomic layer of graphenes to huge galaxies. Currently, it plays a pivot role in many applications such as the manipulation of light and the probing of magnetic fields and material's properties. Basically, this effect causes a polarization rotation of light during its propagation along the magnetic field in a medium. Here, we report an extreme case of the Faraday effect where a linearly polarized ultrashort laser pulse splits in time into two circularly polarized pulses of opposite handedness during its propagation in a highly magnetized plasma. This offers a new degree of freedom for manipulating ultrashort and ultrahigh power laser pulses. Together with technologies of ultra-strong magnetic fields, it may pave the way for novel optical devices, such as magnetized plasma polarizers. In addition, it may offer a powerful means to measure strong magnetic fields in laser-produced plasmas.Comment: 18 pages, 5 figure

Genome-wide identification and characterization of ATP-binding cassette transporters in the silkworm, Bombyx mori

<p>Abstract</p> <p>Background</p> <p>The ATP-binding cassette (ABC) transporter superfamily is the largest transporter gene family responsible for transporting specific molecules across lipid membranes in all living organisms. In insects, ABC transporters not only have important functions in molecule transport, but also play roles in insecticide resistance, metabolism and development.</p> <p>Results</p> <p>From the genome of the silkworm, <it>Bombyx mori</it>, we have identified 51 putative ABC genes which are classified into eight subfamilies (A-H) by phylogenetic analysis. Gene duplication is very evident in the ABCC and ABCG subfamilies, whereas gene numbers and structures are well conserved in the ABCD, ABCE, ABCF, and ABCH subfamilies. Microarray analysis revealed that expression of 32 silkworm ABC genes can be detected in at least one tissue during different developmental stages, and the expression patterns of some of them were confirmed by quantitative real-time PCR. A large number of ABC genes were highly expressed in the testis compared to other tissues. One of the ABCG genes, <it>BmABC002712</it>, was exclusively and abundantly expressed in the Malpighian tubule implying that <it>BmABC002712 </it>plays a tissue-specific role. At least 5 ABCG genes, including <it>BmABC005226</it>, <it>BmABC005203</it>, <it>BmABC005202</it>, <it>BmABC010555</it>, and <it>BmABC010557</it>, were preferentially expressed in the midgut, showing similar developmental expression profiles to those of 20-hydroxyecdysone (20E)-response genes. 20E treatment induced the expression of these ABCG genes in the midgut and RNA interference-mediated knockdown of <it>USP</it>, a component of the 20E receptor, decreased their expression, indicating that these midgut-specific ABCG genes are 20E-responsive.</p> <p>Conclusion</p> <p>In this study, a genome-wide analysis of the silkworm ABC transporters has been conducted. A comparison of ABC transporters from 5 insect species provides an overview of this vital gene superfamily in insects. Moreover, tissue- and stage-specific expression data of the silkworm ABCG genes lay a foundation for future analysis of their physiological function and hormonal regulation.</p

Spatial-temporal analysis of malaria and the effect of environmental factors on its incidence in Yongcheng, China, 2006–2010

BACKGROUND: In 2003, Plasmodium vivax malaria has re-emerged in central eastern China including Yongcheng prefecture, Henan Province, where no case has been reported for eleven years. Our goals were to detect the space-time distribution pattern of malaria and to determine significant environmental variables contributing to malaria incidence in Yongcheng from 2006 to 2010, thus providing scientific basis for further optimizing current malaria surveillance and control programs. METHODS: This study examined the spatial and temporal heterogeneities in the risk of malaria and the influencing factors on malaria incidence using geographical information system (GIS) and time series analysis. Univariate analysis was conducted to estimate the crude correlations between malaria incidence and environmental variables, such as mosquito abundance and climatic factors. Multivariate analysis was implemented to construct predictive models to explore the principal environmental determinants on malaria epidemic using a Generalized Estimating Equation (GEE) approach. RESULTS: Annual malaria incidence at town-level decreased from the north to south, and monthly incidence at prefecture-level demonstrated a strong seasonal pattern with a peak from July to November. Yearly malaria incidence had a visual spatial association with yearly average temperature. Moreover, the best-fit temporal model (model 2) (QIC = 16.934, P<0.001, R(2) = 0.818) indicated that significant factors contributing to malaria incidence were maximum temperature at one month lag, average humidity at one month lag, and malaria incidence of the previous month. CONCLUSIONS: Findings supported the effects of environment factors on malaria incidence and indicated that malaria control targets should vary with intensity of malaria incidence, with more public resource allocated to control the source of infections instead of large scale An. sinensis control when malaria incidence was at a low level, which would benefit for optimizing the malaria surveillance project in China and some other countries with unstable or low malaria transmission

Effect of congenital ptosis on astigmatism and axis length

AIM: To investigate the effects of congenital ptosis degree on total astigmatism, corneal astigmatism, intraocular astigmatism and axis length, and to discuss the relation with amblyopia. <p>METHODS: Fifty patients(100 eyes)with congenital ptosis were selected and divided into four groups: 33 eyes in group Ⅰ(normal); 20 eyes in group Ⅱ(mild); 17 eyes in group Ⅲ(moderate); 30 eyes in group Ⅳ(severity). Firstly, they received standardized medical optometry. Absolute value of astigmatism was recorded as total astigmatism. Then, corneal topography was used to measure double eyes for at least 3 times, and the best results were used to record the SimK. Define absolute value of △SimK as corneal astigmatism. Finally, axial length was measured for 5 times by A super-measurement, and take the mean value. Formula: intraocular astigmatism=total astigmatism-corneal astigmatism.<p>RESULTS: There was a significance difference between total astigmatism and cornea astigmatism(<i>P</i>=0.000, 0.002<0.05). Also they were positive correlation with severity of ptosis(Spearman <i>r</i>_s=0.514, 0.721,<i>P</i><0.05), but there was not significance difference in axial orientation, intraocular astigmatism and axial length(all <i>P</i>>0.05). The axial orientation, intraocular astigmatism had no correlation with severity of ptosis.<p>CONCLUSION: The congenital ptosis affects on eye astigmatism through the change of cornea astigmatism, which is related to severity of ptosis, but has no effect on axial length. The rate of amblyopia is higher than normal on congenital ptosisespecially severity. Amblyopia is related to high astigmatism which is moderate astigmatism with rule